Fires in even the most modern and recently built public multi-story buildings and especially high-rises continually prove the extreme hazard to life in such structures.
In excerpts from the "Fire Journal" and other sources the National Fire Protection Association in Boston, Mass. has documented in a recent booklet entitled "High Rise Building Fires and Fire Safety", many such fires claiming hundreds of lives. On pages 161 through 164 of the March 1973 issue of Reader's Digest an article entitled "How Fireproof Are the New Skyscrapers" as condensed from an article in the Pittsburgh Press by Warren R. Young again indicates the extreme hazard potential of the multi-story building and the need for improvements in the art to safeguard the lives of the occupants. The fire need not be high in a building to cause death as evidenced by the Osaka cabaret fire (see Fire Journal for March 1973) where 118 died and 69 were injured by a fire originating on the third floor of a seven story building.
The case of the high-rise buildings is particularly bad as existing fire fighting equipment and ladders will not reach more than the lower floors of a building and access is only by interior stairs and elevator shafts. In the Sao Paulo, Brazil fire of Feb. 1, 1974 the fire truck ladder could reach to the 11th floor only in a 22 story building where 176 died. Rapid and safe evacuation of people of all ages and states of health down such a tall ladder is at best questionable.
Elevators inside a building are often found to be inadequate as power and central air conditioning systems in the building are vulnerable to fire and smoke. Often the elevator descends to the floor on fire and stops at that point with the occupants unable to move it in either direction.
Stairways and elevator shafts become air ducts for ascending smoke and heat and thus are not dependable as a means for building occupants to either ascend or descend the building. Tragic, frantic attempts are made to flee the fire by improvised ropes and by jumping to death.
Fire fighters as well find it difficult to get to the fire point safely and quickly by elevator or stairways. Modern furnishings contain much plastic which is the source of great volumes of killing smoke in the building.
In the present stage of the art means to evacuate the occupants of a multi-story building on fire consist of the following:
1. outside steel frame fire escape stairways,
2. emergency staircases built into the building,
3. passenger and service elevators in elevator shafts,
4. passenger elevators installed on the outside wall,
5. construction elevators installed temporarily alongside buildings on their own towers, and
6. construction elevators having temporary or permanent rails attached to the outside of a building. See Davis patent U.S. Pat. No. 3,763,964.
Inside staricases and elevator shafts have been found hazardous because they often act as chimneys filled with killing smoke. Staircases of any type are inadequate for evacuating unaided aged and crippled particularly on high rises but certainly on hospitals. External staircases while usually free of smoke, are expensive to maintain, unsightly, and often a ready means to obtain access to a building by those with criminal intent.
While the external elevator should be safer than those in elevator shafts because of more freedom from smoke, the controls in the halls of each floor and dependance upon the building power supply limit their dependability. In addition, the expense involved in providing such elevators in serviceable condition on each wall so as to provide access on a safe wall or walls could easily add a great expense to the building.
Many hours or even several days are required to install the conventional construction elevator therefore eliminating its usefulness in an emergency. While the Davis elevator, U.S. Pat. No. 3,763,964, sugggests an emergency device, it has fallen short of a complete apparatus needed to accomplish the task.
Thus the need for a dependable yet reasonably economical apparatus to evacuate the occupants of a multi-story building has been apparent and yet not met in the prior art. This is especially true of the high rise where even the use of helicopters has been suggested overlooking the possible difficulty of the building occupants to get to the helicopter pad and the hazard of landing a helicopter on a building on fire.